Cooperating set selection for reduced energy consumption and data overhead in downlink CoMP transmission

Coordinated Multi-Point (CoMP) transmission is a recent technology proposed to improve interference mitigation and to increase spectral efficiency in the wireless network. We consider the downlink CoMP joint transmission (JT) in a multi-cell, multi-user system where multiple base stations (BSs) transmit data streams to each user. However, CoMP JT is known to be accompanied by demanding requirements on the backhaul network architecture such as low latency, unlimited backhaul capacity, perfect synchronization and low power consumption. But satisfying all of these conditions seems impossible as the number of BSs transmitting to each user increases. Thus the number of transmit BSs per user has to be limited in order to achieve reduced overhead and affordable backhaul capability. Our main contribution is in formulating the cooperating set (CS) selection problem as two different optimisation scenarios. We evaluate the power consumption and data overhead in these two scenarios while increasing the allowed maximum number of BSs per user.We obtain the optimum CS size such that the total power consumption and backhaul requirements are at their minima in order to achieve the given QoS requirements of each optimisation problem.